The Heckler & Koch grenade machine gun is a fully automatic support weapon in the calibre 40 mm x 53 High Velocity. It is designed to be effective against lightly armoured and unarmoured targets, as well as targets behind cover. The GMG is used to monitor large-scale areas. Pont and area targets can be engaged in direct or indirect fire. Its enormous firepower combined with its large effective area make the GMG the focal weapon in defence against enemy forces or in support of one’s own offensive action. As a force multiplier for infantry and dismounted troops, the GMG is used on a tripod in a covered position, or vehicle-mounted in a weapon station.
The GMG fires belt-linked grenades in 40 mm x 53 calibre with an effective range of up to 1500 metres. Shooting individual rounds is also possible with the GMG. Suitable ammunition types range from fragmentation explosive rounds, battlefield illumination rounds, smoke ammunition for suppressing enemy reconnaissance, flash/bang practice ammunition up to shaped charge warheads used against hardened point and area targets. Using a fire-control system adaptable to the GMG, infrared-programmed airburst rounds can acquire targets behind cover.
The GMG fires 40 mm grenades at a rate of about 340 rounds per minute. It is belt-fed, and can be loaded from either side, making it easy to mount on most platforms. With a variety of day and night sights available, the GMG can be used for most medium range infantry support situations.
The weapon is 1.09 m long and has a 415 mm rifled barrel; the ammunition box has dimensions of 470 × 160 × 250 mm. The gun cycles on a recoil-operated blow-back basis. It weighs 29 kg; the tripod is an additional 11 kg.
Finnish Defence Force Flag day parade in Helsinki Senate Square in 2012. Pasi armoured personnel carrier Heckler & Koch GMG automatic grenade launcher.